Optical networks have become important in today's communication and data networks. Data is transferred using optical fibers, which are generally thinner, cheaper, and lighter than copper cables found in networks that operate in the electrical domain. Moreover, the capacity of optical fibers continues to increase at an extraordinary rate. Optical networks enable large amounts of data to be transferred through optical fibers at very high data rates and over very long distances. Transmission over an optical network may be implemented using a variety of network systems, such as Wavelength Division Multiplexing (WDM), Synchronous Optical Network (SONET)/Synchronous Digital Hierarchy (SDH), and optical packet networks. However, similar to other network technologies, optical networks have their shortcomings.
Despite having a superior medium, optical networks lack the technology to efficiently route and switch the massive amounts of optical data. Optical networks may comprise electrical, optical-electrical, or pure optical components. Unfortunately, development of pure optical components is still in the infancy stages, while electrical components and optical-electrical components are generally too slow to process the massive amounts of optical data. Furthermore, many optical networks require an optical-to-electrical conversion prior to processing the optical signal. The optical-to-electrical conversion transforms the optical signal into an electrical signal. Once in the electrical domain, electrical components, such as switches, routers, and regenerators, may be used to process the electrical signal. Subsequently, an electrical-to-optical converter transforms the electrical signal back into an optical signal. The conversion and electrical processing not only reduces an optical network's throughput, but also increases the complexity of the optical network.
One method to increase routing, switching, and processing speeds in optical networks is to efficiently process the header information encoded in the optical signal, such as a destination address or label. Efficiently processing the header information for an optical signal enables components in a network to execute faster routing or switching decisions. Current technology enables encoding a label or destination address using a single wavelength of light. However, because a transmitting laser operates within a finite range of wavelengths of light and at discrete values, the number of different destination addresses or labels is severely limited for an optical network. As a result, other technological alternatives are necessary to efficiently route optical signals through an optical network without electrical conversion.